From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 298FCC433EF for ; Sun, 6 Mar 2022 22:08:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234304AbiCFWJR (ORCPT ); Sun, 6 Mar 2022 17:09:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229643AbiCFWJP (ORCPT ); Sun, 6 Mar 2022 17:09:15 -0500 Received: from mail-ej1-x62d.google.com (mail-ej1-x62d.google.com [IPv6:2a00:1450:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9831822B0E; Sun, 6 Mar 2022 14:08:22 -0800 (PST) Received: by mail-ej1-x62d.google.com with SMTP id kt27so28266849ejb.0; Sun, 06 Mar 2022 14:08:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=B+OdQEqw3gVimMqDvTK4mctUlemCPrMedCr5iIpp+zM=; b=Qu6f92sIsjPSPety4vCcVtCiuPb634KVCRKpGyaQY8869tDnAjA6x1Gv5st7j1xZHh lT6QhOZr7BnCay8Rzh2OkruAFEWMhgtJGNl/aQt2SCZV28gk9OGhAAN5mCcEYZoQjUNj w+1Z7KyrOTbBvXrrzCcFOhOIbuRE4hOI0LBmY/C2+sv6Wo5KOXPtRMlRDWkUcZk1+U8m jhnOGCxAsDRwvQMhqPczsq+hnTlhjVLbYGSX35JXPCJFVHiaTBaMq1vbSYdZmLZw7cdH 9x/79BDlPAydtMRqvJ1qYORTYmbPX5bMHDQ/CeenyylujzvWyhRnT7BKyq6LVHJFqOB1 F3Gg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=B+OdQEqw3gVimMqDvTK4mctUlemCPrMedCr5iIpp+zM=; b=P/ycxzVogmVZMLVBbO4mwM4VNxQlGM76+9VSWNMuucSh4poRk72lcNT95lh+HQWv+x SSLizoQeLpSkqTlSgsE/fX7PZIKsG16wbTo/TBFw/pJ6sF+GeqqfNtqEAXbSOw0WmG3S Ph+xRS5vACGfvqctnRU2CvMdAHtfvGdyHpHJlC65KmEdSb/NNWSSSqjL6lBms2Aip5uV SQFqr7zs9ffet+54JH18tTyYFSAkCBpblMjinQV5qlrjnnBCtYfHjH+wepFOpbKBwD4L 6/pVMV5ywOLtRM+zV3a4UWneg5TCZwjtFcNTItoKbvegVD3cPMWlByCguDWKijDpn0Cr lgCw== X-Gm-Message-State: AOAM531n32c4mG6vIbLk2zNFLhbXALzvxnCpW/WrF79Pj4fQgKtX8DMs NabD+cRiAfRJibPsgkMrYMXR9DdqULh1KfJG2rnC0514LEA= X-Google-Smtp-Source: ABdhPJxtJPeQPYTwcWknxaOsrytx6gzAfSrsO8vnTvrMWRTFPtLU10WxSJ3igPjaAPfMi3Fv9tDnRcnGtHQF/bM4X4U= X-Received: by 2002:a17:907:6e01:b0:6d0:562c:e389 with SMTP id sd1-20020a1709076e0100b006d0562ce389mr7073620ejc.497.1646604501024; Sun, 06 Mar 2022 14:08:21 -0800 (PST) MIME-Version: 1.0 References: <20220302095606.14818-1-ilpo.jarvinen@linux.intel.com> <20220302095606.14818-2-ilpo.jarvinen@linux.intel.com> <20220306184857.GA19394@wunner.de> In-Reply-To: <20220306184857.GA19394@wunner.de> From: Andy Shevchenko Date: Mon, 7 Mar 2022 00:07:44 +0200 Message-ID: Subject: Re: [PATCH 1/7] serial: 8250_dwlib: RS485 HW half duplex support To: Lukas Wunner Cc: =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , "open list:SERIAL DRIVERS" , Jiri Slaby , Greg Kroah-Hartman , Linux Kernel Mailing List , Johan Hovold , Andy Shevchenko , Heikki Krogerus , Raymond Tan , Heiko Stuebner Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 7, 2022 at 12:00 AM Lukas Wunner wrote: > On Wed, Mar 02, 2022 at 11:56:00AM +0200, Ilpo J=C3=A4rvinen wrote: ... > Does the DesignWare UART use dedicated DE and RE pins instead of > the RTS pin? That would be quite unusual. They are muxed with other UART pins on SoC level, but I don't remember by heart which ones. According to the Synopsys datasheet they are separate signals. It might be that I'm missing something, since the last time I looked was last year. ... > > + d->hw_rs485_support =3D device_property_read_bool(p->dev, "snps,r= s485-interface-en"); > > + if (d->hw_rs485_support) > > + p->rs485_config =3D dw8250_rs485_config; > > + > > You wrote in the commit message that rs485 support is present from > version 4.0 onward. Can't we just check the IP version and enable > rs485 support for >=3D 4.0? That would seem more appropriate instead > of introducing yet another new property. AFAIU this is dependent on the IP syntheses. I.o.w. version 4.0+ is a prerequisite, but doesn't automatically mean that there is a support. Unfortunately there is no way to tell this clearly in the IP configuration register. --=20 With Best Regards, Andy Shevchenko